Final answer:
The generator alerts the ECS when less than 1 hour of fuel remains, based on either running at full power for 12 hours or at half power for 24 hours. Specific details about the generator's specifications were not provided, making a more accurate calculation challenging.
Step-by-step explanation:
The generator in question appears to be part of an Environmental Control System (ECS) and the query is focused on the low fuel warning it provides. Although the exact amount of remaining runtime for the generator that triggers the alert to the ECS is not provided in the question, the information hints at a procedure to calculate it based on generator output at full or half power. To compute the warning threshold, one might assume a generator that has either 12 hours of runtime at full power or 24 hours at half power.
So, if a generator can operate for 12 hours, the warning would be set to alert the ECS when less than 1 hour of fuel remains. Without the precise scenario and generator specifications, it is difficult to provide a more specific answer. The information about 3 s (green flame) engines using a liquid fuel/oxidant mixture and 4 s (yellow flame) engines using a solid mixture seems related to engine types and their fuel systems but does not directly relate to the ECS fuel state alert system.